This invention relates to a method of and an apparatus for compacting coking coal in a pounding box.
When certain kinds of bituminous coal are to be used for coking, a satisfactory coking process is assured only if the coal is first compacted by pounding it with punners into a kind of cake. This applies in particular to a highly volatile coal.
Compacting of the coal by punners involves introducing the coal in layers outside the coke oven into a pounding box and compacting it therein into a cake which is then pushed into the over chamber. Compaction of the coking coal is effected by the punners; usually, several of these are mounted in punner carriages which can be moved to and fro lengthwise over the pounding box while the feet of the punners pound the coking coal and are then lifted off again, i.e., the punners alternately drop onto and are lifted off the coal.
It has been found that the properties of the coke obtained from pounded coal, particularly the formation of cracks in the coke and its mechanical strength, depend directly upon the density of compaction which is achieved. It is therefore desired to achieve the greatest possible degree of compaction within the shortest possible time throughout the volume of coal in the pounding box, and at the same time to so compact the coal that its density of compaction is uniform throughout the cake. However, the techniques which have been developed for this purpose still leave something to be desired.